FIG. 1 depicts a portion of a conventional energy assisted magnetic recording (EAMR) transducer 10. The conventional EAMR transducer 10 includes a conventional waveguide 12 having a conventional core 18 and cladding 14 and 16, a grating 20, a conventional near-field transducer (NFT) 30, and a write pole 40. The NFT 30 has a disk portion 34 and a pin portion 32. The pin portion 32 is between the disk portion 34 and the air-bearing surface (ABS). The conventional EAMR transducer 10 is used in writing to a recording media and receives light, or energy, from a conventional laser (not shown). In operation, light from a laser is coupled to the waveguide 12. Light is guided by the conventional waveguide 12 to the NFT 30 near the ABS. The NFT 30 utilizes local resonances in surface plasmons to focus the light to magnetic recording media (not shown), such as a disk. The surface plasmons used by the NFT 30 are electromagnetic waves that propagate along metal/dielectric interfaces. At resonance, the NFT 30 couples the optical energy of the surface plasmons efficiently into the recording medium layer with a confined optical spot which is much smaller than the optical diffraction limit. This optical spot can typically heat the recording medium layer above the Curie point in nano-seconds. High density bits can be written on a high coercivity medium with a pole 40 having modest magnetic field.
FIG. 2 depicts a conventional method for providing the NFT 30 in the conventional EAMR transducer 10. Referring to FIGS. 1 and 2, a layer of conductive material is deposited for the NFT, via step 52. Typically the conductive material is gold. The conductive layer is masked, via step 54. The mask covers the portion of the conductive layer that will form the NFT 30. The exposed portion of the conductive layer is removed, via step 56. Step 56 typically includes performing an ion mill. More specifically, an overmill step is performed. The overmilling ensures that the walls of the NFT 30 are vertical and that any tail from the conductive layer is completely removed from the region surrounding the NFT 30. Thus, the NFT 30 is formed. Fabrication of the conventional EAMR transducer 10 may then be completed.
Although the conventional method 10 may form the conventional NFT 30, there are drawbacks. In particular, fabrication of the conventional NFT 30 may have low yield and/or higher variations than desired. For example, the overmilling in step 56 may result in a significant variation in the critical dimensions of the conventional NFT 30. The conventional NFT 30 is on the order of fifty nanometers thick. If overmilling is not performed, then the walls of the NFT 30 may not be vertical. The top of the NFT 30 shown as dotted lines in FIG. 1) may be less wide than the bottom of the NFT 30 (shown as a solid line in FIG. 1). Thus, there is a variation of the critical dimension within the NFT, shown as CDA and CDB, of the conventional NFT 30. Thus, variations in the critical dimensions may still occur even if overmilling not performed. Further, the conventional core 16 of the waveguide 12 is on the order of ten to fifteen nanometers thick. The overmilling in step 58 may remove a significant portion of the core 16. Thus, step 58 may damage the underlying waveguide 12, which is undesirable.
Accordingly, what is needed is a system and method for improving manufacturability of an EAMR transducer.